Espectroscopia eletronica aplicada ao estudo de relaxações de polimeros estirados

AUTOR(ES)

Marcio Talhavini

DATA DE PUBLICAÇÃO

1995

RESUMO

The relaxations of low density polyethylene (LDPE) and poly(vinyl acetate) PVAc have been probed by luminescence spectroscopy of anthracene (fluorescent) molecules dissolved (or covalently linked to) in the polymeric matrix. The LDPE sample has been studied in two ways: unstretched, and 500% uniaxially stretched; The stretched films were analysed with both, unpolarized and plane-polarized light excitation and emission. The basic objectives of this work were: 1) to build a microcomputer interfaced spectrofluorimeter coupled to a helium cryostat; 2) to use the instrument to determine the relaxation processes of LDPE (stretched and unstretched) and PVAc. Three LDPE relaxations were detected, and their molecular origins vvere determined: a, that appears between 310K - 330K and is related with the presence of polymer crystals. b, at 230K, which occurs in amorphous phase. g, between 120K - 150K. and, like a, is related to the crystals.

ASSUNTO(S)

espectroscopia eletronica polimeros

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